Mach-O ld64 supports -w to suppress warnings. GNU ld 2.40 will support the
option as well (https://sourceware.org/bugzilla/show_bug.cgi?id=29654).
This feature has some small value. E.g. when analyzing a large executable with
relocation overflow issues, we may use --noinhibit-exec --emit-relocs to get an
output file with static relocations despite relocation overflow issues. -w can
significantly improve the link time as printing the massive warnings is slow.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D136569
```
template <typename T> struct A {
A() {}
int value = 0;
};
template <typename Value> struct B {
static A<int> a;
};
template <typename Value> A<int> B<Value>::a;
inline int foo() {
return B<int>::a.value;
}
```
```
clang++ -c -fno-pic a.cc -o weak.o
g++ -c -fno-pic a.cc -o unique.o # --enable-gnu-unique-object
# Duplicate symbol error. In postParse, we do not check `sym.binding`
ld.lld -e 0 weak.o unique.o
```
Mixing GCC and Clang object files in this case is not ideal. .bss._ZGVN1BIiE1aE
has different COMDAT groups. It appears to work in practice because the guard
variable prevents harm due to double initialization.
For the linker, we just stick with the rule that a weak binding does not cause
"duplicate symbol" errors.
Close https://github.com/llvm/llvm-project/issues/58232
Differential Revision: https://reviews.llvm.org/D136381
A reference to __real_foo should trigger archive extraction of the input file that defines foo, otherwise a link using --wrap=foo might fail to link with an undefined reference to foo.
This matches bfd linker behaviour.
Differential Revision: https://reviews.llvm.org/D135897
The target-specific code (AArch64, PPC64) does not fit into the generic code and
adds virtual function overhead. Move relocateAlloc into ELF/Arch/ instead. This
removes many virtual functions (relaxTls*). In addition, this helps get rid of
getRelocTargetVA dispatch and many RelExpr members in the future.
{D116279}, in addition to adding support for other demanglers, also
factored out some of the demangling logic. However, I don't think the
abstraction really carries its weight -- after {D135942}, only the ELF
and WASM backends call it with anything other than a non-constant
`shouldDemangle` argument. The COFF and Mach-O backends were already
doing the should-demangle check before calling `demangle()`.
Reviewed By: MaskRay, #lld-macho
Differential Revision: https://reviews.llvm.org/D135943
This reverts commit 096f93e73dc3f88636cdcb57515e3732385b452d.
Revert "[Libomptarget] Make the plugins ingore undefined exported symbols"
This reverts commit 3f62314c235bd2475c8e2b5b874b2932a444e823.
Revert "[LLD] Enable --no-undefined-version by default."
This reverts commit 7ec8b0d162e354c703f5390784287054601f9c69.
Three commits are reverted because of the current omp build fail
with GNU ld. See discussion here: https://reviews.llvm.org/rG096f93e73dc3
Allowing incorrect version scripts is not a helpful default. Flip that
to help users find their bugs at build time rather than at run time.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D135402
Currently when the --thinlto-emit-index-files is used with LLD and a
thin archive is passed containing references to object files to link
against where the object files are in a different folder than the thin
archive and some of the archives aren't linked against (ie stay lazy),
the empty index file writer ends up trying to write to a path that
doesn't exist. This patch changes the behavior of that function to use
the path of the obj member of the BitcodeFile object rather than just
the path of the BitcodeFile object itself, which matches the behavior of
the default (non-lazy) case.
Fixes#57963
Regression test added.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D135014
Add LLVM_LIBRARY_VISIBILITY to remove unneeded GOT and unique_ptr
indirection. We can move other global variables into ctx without
indirection concern. In the long term we may consider passing Ctx
as a parameter to various functions and eliminate global state as
much as possible and then remove `Ctx::reset`.
`config` has 1000+ uses so we try to avoid changing `config->foo`. Define a
wrapper with LLVM_LIBRARY_VISIBILITY to remove unneeded GOT and unique_ptr
indirection.
My x86-64 lld executable is 11+KiB smaller.
Symbol::replace intends to overwrite a few fields (mostly Elf{32,64}_Sym
fields), but the implementation copies all fields then restores some old fields.
This is error-prone and wasteful. Add Symbol::overwrite to copy just the
needed fields and add other overwrite member functions to copy the extra
fields.
For RVC, GNU assembler and LLVM integrated assembler add c.nop followed by a
sequence of 4-byte nops. Even if remove % 4 == 0, we have to split one 4-byte
nop and therefore need to write the code sequence, otherwise we create an
incorrect c.unimp.
This fixes a regression since fa74144c64dff6b145b0b3fa9397f913ddaa87bf;
even if we're linking to the dylib (which handles all the dependencies
in LLVMSupport), we're now also directly referencing zstd from
lld/ELF, and thus need to explicitly express our dependency on it.
https://reviews.llvm.org/D133003#3806508 can reproduce a non-determinism with
--threads=4. Making the config serial fixes non-determinism (by running the link
many times and compare output).
See D117853: compressing debug sections is a bottleneck and therefore it
has a large value parallizing the step.
zstd provides multi-threading API and the output is deterministic even with
different numbers of threads (see https://github.com/facebook/zstd/issues/2238).
Therefore we can leverage it instead of using the pigz-style sharding approach.
Also, switch to the default compression level 3. The current level 5
is significantly slower without providing justifying size benefit.
```
'dash b.sh 1' ran
1.05 ± 0.01 times faster than 'dash b.sh 3'
1.18 ± 0.01 times faster than 'dash b.sh 4'
1.29 ± 0.02 times faster than 'dash b.sh 5'
level=1 size: 358946945
level=3 size: 309002145
level=4 size: 307693204
level=5 size: 297828315
```
Reviewed By: andrewng, peter.smith
Differential Revision: https://reviews.llvm.org/D133679
In GNU ld,
* --version skips linker input processing.
* -v and -V keep processing if there is any input file. -V has more
information we don't support.
We currently make -V an alias for --version which skips input processing.
On many `*-freebsd` and `powerpc-*` targets, `gcc -v` passes `-V` to ld
and expects to process input. Make -V an alias for -v to provide
compatibility.
Fix https://github.com/llvm/llvm-project/issues/57859
They may modify thinlto optimization.
This patch only extends support for `-mllvm`. There is another way to
pass llvm flags, `-plugin-opt`, but its processing is different and will
be provided in a subsequent patch.
Differential Revision: https://reviews.llvm.org/D134013
This improves consistency with other places (e.g. llvm::compression::decompress,
llvm::object::Decompressor::decompress, llvm-objcopy).
Note: when zstd::uncompress was added, we noticed that the API `ZSTD_decompress`
is fine while the zlib API `uncompress` is a misnomer.
On Unix platforms, this wrapper function is inline, so it should
expand to the same direct access to the thread local variable. On
Windows, it's a non-inline function within Parallel.cpp, allowing
making the thread_local variable static.
Windows Native TLS doesn't support direct access to thread local
variables in a different DLL, and GCC/binutils on Windows occasionally
has problems with non-static thread local variables too.
This fixes mingw dylib builds with native TLS after
e6aebff67426fa0f9779a0c19d6188a043bf15e7.
At the same time, move the whole thread local variable within
#if LLVM_ENABLE_THREADS
to fix builds without threading support.
Differential Revision: https://reviews.llvm.org/D133759
